Roemer and I tasted some delicious espresso today from Wouter Strietman's ES3 which is almost in production now. A number of custom parts is currently in serial production with the man who is also doing metal work for Kees van der Westen and when they arrive, it will not take long for the first customers to get this latest version of the Strietman range.
On our way home, Roemer edited some of the footage we (mostly he) shot during the visit:
What struck me is how open and communicative Strietman is about many details of his design and the learning curve he has been going through since desiging and selling his first Espresso Strietman model. He seems to fit very well in the world of young coffee entrepeneurs, where very few people hold their cards to their chest.
Sometimes he wished he'd had 20 years of experience in the development of prototypes already but luckily he knows people who have and he learns from them. For instance, one senior sharing the huge workshop full of machines and parts to work with wood and metal has been a lifelong prototype / mockup engineer for Philips.
On the floor below one of his work benches, Strietman has three huge classical vintage machines that he has practically stripped to study the work of the earlier espresso machine designers. One machine with a boiler that looks bomb proof has a huge brew head where line pressure is hydraulically converted to 9 bar pressure, another is the E64 brew group and the third an old dual group lever.
On the table, some test samples of copper plates turned into a half ball and a cone, one done using a slow pressure method, "diepdruk" that's time consuming and the other by using a mold and stamping technique. For the top cone of his ES3, the time consuming method is used as it costs about ten thousand Euros to get a mold to create the cones in a quicker fashion.
The workshop is filled with pleasant jazz music from Strietman's sizeable collection of mostly jazz vinyl records. His stereo is on a high plateau above his work space:
Jazz and more
It's also a storage for the early ES boxes. Strietman has since learned that he needs bigger boxes and sturdier foam filling to buffer all the abuse that couriers can do to a parcel after they picked it up.
In a corner of his work space is a small collection of early models and parts:
A very early model
One very early model is a stand up version which can deliver steam too. The bottom half of the brew head is somewhat traditional for a lever, since raising the piston opens a hole in the side for boiler water to flow in. On top of the brew head is a tiny water container which can be filled, by lever action, with hot water that's pressed down into the (partly visible) block heater where it will be suddenly heated to steam which presses out a little steam wand, so milk can be frothed and heated up for cappuccino.
Already a small museum of "old" models and parts
Some parts of the current production
Recent good news has been that his ES3 passed the tests required to carry the CE rating and it shows:
ES3 brew head part with CE logo
More parts
Strietman shows us the detailed work of his piston, which is essentially different from pistons in the La Pavoni or CMA like models (Idrocompresso, LONDINIUM). In a La Pavoni lever, when you lift the piston you first create a little vacuum and air is sucked through the puck in the space above the coffee puck. Then one or more inlet holes for hot water are opened by the retreating seals of the piston and water pours in. The Strietman piston, when raised, immediately allows hot water from the open boiler to come through the center of the piston, downwards on the coffee puck that's tightly packed between basket and dispersion screen.
About these baskets: they are the same 50mm size as the pre-millennium La Pavoni levers and some of these owners may be thrilled to hear that Strietman has ordered the production of several hundreds of special baskets which have much more precise holes. The VST baskets and their quality prompted him to get a similar rate of precision for his ES3.
He showed us one and we were quick to pre-order a few from him. Since I only have one pre-millennium La Pavoni, I will be able to give a few of those away.
Strietman is fascinated by the fact that so much of the espresso technology is still very close to the level of development of the fifties and sixties. It's charming to have this technology lasting all those years basically unchanged, but it also poses a challenge for some to try and outdo the masters, developing a simple machine that takes some of it all a few steps ahead.
Then he makes us some shots of fine espresso. The first cup was absolutely delicious and the others were very good as well but quite different, even though he used the same Ethiopian beans for all the shots. He demonstrated that a slightly finer or courser grind and a slightly higher or lower temperature setting of the ES3 can make a lot of difference. Some like a shot that tastes like successful shot from a La Pavoni, others prefer a light and fragrant shot that brings to mind specialty filter coffee extraction. Each can be accomplished with the right tweaks in the hands of a maker.
Strietman knows he should buy or make his own tamper...
Pre-infusion
Watching the first drops (picture by Roemer)
Flow
Observing flow (picture by Roemer)
The machine and its maker staring at one another (picture by Roemer)
(also see Daily Coffee News feature ) Tije designed and made the following structure for a tiny and cheap fluid bed roaster, to which Jan van der Weel added the Arduino parts, electronics and programming: Sketch by Tije de Jong Jan sourced a very cheap blower (€ 11) to start with, Tije developed and constructed the mechanics, Jan built together and programmed the TC4 / SSR electronics. On his blog, Jan will specify exactly how the TC4 part is combined and programmed and I will copy these details into this blog entry, just as Jan will use this video in his blog. We did a few test roasts to make sure it works at all and it does. Towards the end, the first roast tended to get a flat BT line and airflow was slightly decreased. 200g seems max load of green beans. Second roast a little more power was given to the heater. Next we will try the Background Roast driven by the PID software of Artisan. A week later, with updated software that works better to change the fan
Delicious cup: all the work was well invested! At the end of the previous blog about the pressostat and PID working together , I mentioned that I would like to clean up the xmas tree of wires and have as few cables and probes as possible to visually disturb the classic design of the La Pavoni. Getting rid of the probe that was fastened with copper tape to the top of the brew group was a priority. I wanted to hide a new probe in the cooling fin as close as possible to the brew group. This morning I asked Tije if he could do that. He would need to drill a straight hole of 3mm diameter in the 4mm inner ring of the cooling fin that sits as a tight clamp around the brew group. Always the optimist, Tije set to work: First, Tije made a piece of aluminum to fit the inside of the ring. Drilling a thin hole straight through the curved aluminum, if possible tangentially going through the inside of the ring to touch the brew head directly, you need the support of the temporary insid
illustration by Matthias Gerstgrasser On the mailing list for Artisan users , Matthias Gerstgrasser posted a report about his coffee roaster project, with a link to a beautifully illustrated, complete step by step guide of his work on Instructables: A while ago I posted a few messages on here regarding automation for my hot-air popcorn roaster, and was asked if I could share a writeup of what I had been doing with my setup. I know it’s been a long time, but I haven’t forgotten, just got a little sidetracked (more on that below). I have finally found time to do this over the last few weeks though, and compiled a step-by-step guide of how I modified my popcorn machine. This is now available on Instructables: https://www.instructables.com/id/Arduino-controlled-DIY-Coffee-Roaster/ Do let me know if there’s anything missing or anything that could be improved. I intend to keep updating the guide as I find ways to improve it or as new developments occur. I am also discussing b
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